When underground lines are laid, it is generally necessary and/or desirable, to have one or more underground valves in the lines for use in controlling the flow of the material through the lines. Even if valves are not present in the lines, it is generally desirable to have access boxes which allow one to obtain access to the underground line at various locations.
The use of underground valves has necessitated the use of valve boxes, also often referred to as "curb" boxes, to allow one a means of obtaining access to the valves without having to dig down in the earth to uncover the valve.
The curb boxes currently in use are generally tubular casings having an enlarged lower bell housing that encompasses the valve. The upper end of the valve box generally includes a cover which is generally flush with the ground surface. Typically, an elongated wrench is used to reach down into the curb box to turn the valve operating knob, which is often referred to as a valve head.
Early curb boxes were constructed of cast iron, and most lines and valves were also metallic. With the advent of synthetic polymeric materials, the lines, valves, and boxes are now being replaced with similar components formed of synthetic plastic. Although synthetic plastic lines and valves are more resistant to the deterioration that accompanies the corrosion and aging of metal, the use of synthetic plastic components raises other engineering considerations that were not posed by early metallic components. For example, the use of plastic valves and plastic lines generally makes it more critical that the valve operating head not be exposed to torque that would damage either the line, the valve, or the valve line connection.
An object of the present invention is to provide a valve box which helps preclude the shifting of the valve relative to the line when the valve operating head is turned.
Another object of the present invention is to provide an elongated valve operating device, or high head, which includes a frangible component which is designed to shear if force is applied which might damage the valve or line.
Still another object of the present invention is to provide means allowing for the location of underground non-metallic valves or lines with a metal detector.
Still yet another object of the present invention is to provide an adaptor which allows one to use one elongated valve operating device for both of the two types of valve heads that are now generally encountered.
Still yet another object of the present invention is to provide access boxes and/or operating heads which are constructed of a synthetic plastic which is color-coded to designate the type of utility line with which they should be employed.
Other aspects, objects, and advantages of the present invention will be apparent to one having the benefit of the following disclosure and its accompanying drawing.